ISSN:
1573-5117
Schlagwort(e):
Pelecus cultratus
;
food
;
selectivity
;
fish predation
;
prey visibility
;
zooplankton
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Pelecus cultratus (razor fish), a cyprinid fish, has become a dominant species in Neusiedler See. Gut content analyses of 400 specimens collected in 1989 and 1990 showed that Pelecus fed mainly on large zooplankton (Diaphanosoma, Leptodora and Arctodiaptomus), although their diet also included Insecta (larvae, pupae and adults) and Arachnida (spiders), occasionally small fishes. Comparison of the relative abundance of the zooplankton species in the stomach to the lake indicated that Pelecus strongly selected cladocerans over copepods, and fed mostly on large-sized individuals of Diaphanosoma, Leptodora and Arctodiaptomus. The fish showed a significant positive selectivity only for individuals of Diaphanosoma 〉 1.0 mm and Leptodora 〉 4.0 mm. In contrast, selectivity increased continuously in relation to the diameter of the compound eye of both prey species. This suggested that prey visibility was a key factor in determining the prey selectivity by Pelecus. It also seems likely that the persistence of the Leptodora population in Neusiedler See can be attributed to negligible predation pressure on the smaller sized individuals of this species.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00017569
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